Pipe stderr windows

Viewed k times. Improve this question. A similar question, but retaining stdout: unix. I was expecting something like this: command 2 othercommand. Bash is so perfect that development ended in , so we'll never see that in bash, I'm afraid. Rolf What do you mean?

Show 4 more comments. Active Oldest Votes. Improve this answer. Jonathan Leffler Jonathan Leffler k gold badges silver badges bronze badges. They will be marginally less efficient unless the shell treats them as special cases; the pure numeric notation doesn't involve accessing files by name, but using the devices does mean a file name lookup. Whether you could measure that is debatable. I like the succinctness of the numeric notation - but I've been using it for so long more than a quarter century; ouch!

KurtPfeifle: au contraire! One must read the redirection chains from left to right since that is the way the shell processes them. Right-to-left wouldn't work.

Show 24 more comments. Peter Mortensen Kramish Kramish 3, 1 1 gold badge 12 12 silver badges 2 2 bronze badges. Can we create a file descriptor that has stderr and another that has the combination of stderr and stdout? In other words can stderr go to two different files at once? JonathanLeffler Out of curiosity, does your tweak serve any purpose performance-wise, other than perhaps clarifying the role of file descriptor 3 for an observer? In truly arcane situations, it might make the difference between a process detecting and not detecting EOF, but that requires very peculiar circumstances.

Caution : this assumes FD 3 is not already in use, doesn't close it, and doesn't undo the swapping of file descriptors 1 and 2, so you can't go on to pipe this to yet another command. See this answer for further detail and work-around. Show 8 more comments. Jonathan Leffler k gold badges silver badges bronze badges. Connect and share knowledge within a single location that is structured and easy to search.

Some programs would prefer to output the help message in stderr. Sign up to join this community. The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Learn more. How to pipeline stderr in cmd. Ask Question. Feedback will be sent to Microsoft: By pressing the submit button, your feedback will be used to improve Microsoft products and services.

Privacy policy. Returns 0 if successful. Returns -1 to indicate an error. On error, errno is set to one of these values:. EINVAL , which indicates that either the array pfds is a null pointer or that an invalid value for textmode was passed in.

A pipe resembles a file because it has a file pointer, a file descriptor, or both, and it can be read from or written to by using the Standard Library input and output functions. However, a pipe does not represent a specific file or device. Instead, it represents temporary storage in memory that is independent of the program's own memory and is controlled entirely by the operating system.

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